Cracks In Wall Plaques/tiles

Hello! I create wall plaques (like layed tiles) and I am having serious crack problems. At first, I was only having cracks in these pieces in the glaze kiln, but now I am getting cracks in the bisque kiln as well. I have tried several solutions suggested to me, but the problem still exists. The cracks are in the bottom of the pieces (side touching shelf) and sometimes will come through to the front of the piece. They mainly begin at the top of the piece and go towards the center, but not always. Some cracks are very slight, and some are pretty deep and wide.

Please advise... I have boxes of plaques with cracks and it is very disheartening to loose so many pieces.

We need lots more info before we can even start.How do you build them?Did they ever fire just fine?What kind of clay?What firing temp?What kind of firing profile?j

Thank you for your help!

I use a portable slab roller to make slabs about 3/8"thick and texture them - cut into squares about 6" x 6" or so; on top of piece slip and score a thinner textured flat piece of clay; on top of that slip and score a thinner piece of clay with my phrase or quote. On the back, I insert an inverted U-shaped piece of high-fire wire for hanging about an inch or so from the top.

I do have pieces that fire fine, I'm finding 10 - 20% of each load have these cracks. The problem is now occuring in the bisque kiln when before it was only in the glaze kiln. Cannot see the connection between the pieces that are cracking

I bisqued several plaques standing up as suggested, but still got some cracks - these were already constructed before the other suggestions. Sounds like it might be in the construction and not the firing (?). Next time I make plaques I will try the rolling advice... I'm looking forward to seeing what happens!

I roll out slabs on a 30 inch slab roller and turn the direction..similar to Chris' suggestion. I dry my slabs on sheet rock with a liner of newsprint paper between the sheet rock and clay. This allows shrinkage movement. Then I wax the edges about 1-2" around the entire slab. This prevents the edges from drying too fast and prohibits warping. My slabs are as large as 25 inches.
So: rotate the slab to reduce stress...alleviate by rotating or with a rolling pin.
let it dry without sticking to the surface
dry it slowly by wrapping it, use sheetrock, and wax the edge.